refactor(edge): Server 协议统一与 wsclient 收敛（Phase 3 Batch 3）

- openflare/agent/relay/flared 协议类型改为 pkg/protocol 别名，删除重复 struct
- 新增 edge/wsclient Preset 表，三组件 wsclient 改为薄包装
- 更新设计文档、计划与 changelog

internal/apps/openflare/agent/protocol_alias.go

@@ -0,0 +1,26 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package agent
+
+import pkgprotocol "github.com/Rain-kl/Wavelet/pkg/protocol"
+
+type NodePayload = pkgprotocol.NodePayload
+type NodeSystemProfile = pkgprotocol.NodeSystemProfile
+type NodeMetricSnapshot = pkgprotocol.NodeMetricSnapshot
+type NodeOpenrestyObservation = pkgprotocol.NodeOpenrestyObservation
+type NodeTrafficReport = pkgprotocol.NodeTrafficReport
+type NodeAccessLog = pkgprotocol.NodeAccessLog
+type BufferedObservabilityRecord = pkgprotocol.BufferedObservabilityRecord
+type NodeHealthEvent = pkgprotocol.NodeHealthEvent
+type ApplyLogPayload = pkgprotocol.ApplyLogPayload
+type Settings = pkgprotocol.AgentSettings
+type ActiveConfigMeta = pkgprotocol.ActiveConfigMeta
+type SupportFile = pkgprotocol.SupportFile
+type WAFIPGroup = pkgprotocol.WAFIPGroup
+type WAFIPGroupSyncRequest = pkgprotocol.WAFIPGroupSyncRequest
+type WAFIPGroupSyncResponse = pkgprotocol.WAFIPGroupSyncResponse
+
+// Backward-compatible names used by server routers and handlers.
+type WAFIPGroupSyncInput = WAFIPGroupSyncRequest
+type WAFIPGroupSyncResult = WAFIPGroupSyncResponse